Domestic violence and sexual assault crimes are among the most sensitive and challenging cases to investigate and prosecute. They involve extremely personal information, which the prosecution needs and the defense may demand, and which victims are understandably reluctant to share. The purpose of this article is to help criminal justice professionals understand what kinds of information victims generally consider to be private and to facilitate their ability to explain—to victims and other professionals—what information is legally protected as private. This Strategies article is Part I of a two-part series addressing two types of legally protected information: confidentiality and privilege. Part I provides an overview of confidentiality to assist prosecutors in balancing offender accountability with the safety needs and expectations of victims during criminal investigations and prosecutions.